1. Field of the Invention
The present invention generally relates to the field of vehicular wheel suspensions. More particularly, the present invention relates to the field of improved wheel suspensions for providing kneeling function to a vehicle, such as vans, having a lowered floor.
2. Description of the Prior Art
U.S. Pat. No. 4,067,558 issued to Keijzer et al. on Jan. 10, 1978 discloses a vehicle wheel suspension strut wherein the conventional suspension unit may be converted to an air leveling or air adjustable type suspension without requiring the discarding of the original shock absorber and/or related components. The converted wheel suspension incorporates virtually all of the original components, which are supplemented with a rolling type diaphragm element that cooperates with the original components in defining a variable volume air chamber which can be selectively supplied with compressed air or some other suitable fluid to provide the load adjustable characteristics. However, this suspension system does not provide a kneeling function, which causes the vehicle floor to be lowered when the vehicle is parked.
Specifically, rear suspensions on vehicles, such as vans, are well known in the art. These prior art rear suspensions on front wheel drive vehicles typically include a rear axle, two coil springs, two shock absorbers and a rear axle tie rod. One example is the General Motors (GM) Venture.TM. van, where the rear suspension has coil springs. However, this rear suspension has no kneeling function.
In mobility industry, a vehicle is often modified to have a lower floor with a floor level lower than the original one (for example approximately 12 inches lower) as to provide more interior height for physically challenged people. The initial vehicle's floor is cut and replaced by a new designed floor for the modification. To compensate and have enough clearance between the vehicle floor and the ground, prior art spacers are mounted relatively to the rear suspensions at the bottom of the coil springs to raise the modified vehicle body certain distance (for example approximately 2 inches). However, this modified vehicle has no kneeling function while it is needed on some lower floor mobility vans especially for which equipped with wheelchair lifts or ramps required to lower the vehicle floor even closer to the ground floor during entrance and exit of the vehicle. Therefore, it is desirable to provide a lower floor vehicle with a kneeling function.